本文關(guān)鍵詞： 石墨插層化合物 石墨烯分散液 高濃度 高收率 超級電容器　出處：《華東理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：本文采用電化學法在無機酸/無機鹽水溶液中插層剝離陽極石墨棒,制備了石墨插層化合物(GIC_s),以此為原料,采用液相剝離法制備了高濃度穩(wěn)定的石墨烯分散液�？疾炝穗娊赓|(zhì)性質(zhì)、電解液濃度以及電壓對GIC_s層間距和氧化程度的影響;探討了 GIC_s的結(jié)構(gòu)、分散體系、超聲時間、原料濃度等對所制備石墨烯分散液濃度的影響,以及影響石墨烯收率的因素。并得到制備高濃度石墨烯分散液的最優(yōu)工藝條件。然后以石墨烯作為超級電容器的電極材料,考察不同因素對超級電容器電化學性能的影響。結(jié)果如下:1.不同電解質(zhì)對石墨電化學剝離速率由大到小的順序是:H_2SO_4、Na_2SO_4、H_3P0_4、(NH_4)_2HP0_4;S042-作為插層陰離子效果較好,由于硫酸的氧化性較強,所制備的GIC_s氧化程度較高。2.在Na_2SO_4溶液中電化學插層剝離,所獲得的GIC_s層間距隨電壓、電解液濃度的升高而增大,同時其剝離速率也提高。當Na_2S0_4電解質(zhì)濃度為0.5 M、電壓為14 V時,電化學剝離最快,產(chǎn)物GIC_s層間距由石墨的0.3358 nm變?yōu)?.3381 nm,且含氧量也較低9.04%,是制備石墨烯的良好前軀體。3.在最優(yōu)工藝條件下,石墨烯分散在NMP中的濃度高達11.47 mg/mL,同時收率為37%;在PVP/水中石墨烯的濃度也達到4.45 mg/mL,收率為14.8%。所獲得的石墨烯尺寸都在1 μm左右,層數(shù)較少(少于10層),晶型結(jié)構(gòu)較為完整,C/O比值高,缺陷主要是邊緣缺陷,沉降實驗表明分散液是非常穩(wěn)定的。4.將石墨烯分散液作為電極活性物質(zhì)的原料,采用扣式結(jié)構(gòu)制作了石墨烯電極超級電容器,研究了電容器的組裝工藝。探討了電極成型壓力、粘結(jié)劑用量對電容器電學性能的影響。以10 MP_a成型壓力、5 wt.%的粘結(jié)劑含量制作電極,在6 mol/LKOH水系電解液中恒電流0.5 A/g下石墨烯超級電容器的比容可以達到162 F/g,能量密度也達到22.5 Wh/kg,并且具有較好的充放電循環(huán)性能。
[Abstract]:In this paper, a graphite intercalation compound (GICS) was prepared by intercalating the anode graphite rod in inorganic acid / inorganic salt aqueous solution by electrochemical method, which was used as raw material. High concentration and stable graphene dispersion was prepared by liquid phase stripping method. The effects of electrolyte properties, electrolyte concentration and voltage on the interlayer spacing and oxidation degree of GIC_s were investigated. The effects of the structure of GIC_s, dispersion system, ultrasonic time and concentration of raw materials on the concentration of graphene dispersion were discussed. And the factors affecting the yield of graphene were obtained. The optimum process conditions for preparing high concentration graphene dispersion were obtained. Then graphene was used as electrode material for supercapacitor. The effects of different factors on the electrochemical properties of supercapacitors were investigated. The results are as follows: 1. The order of electrochemical stripping rate of graphite from different electrolytes to graphite is: 1. H3P0 / hp0 / hp0 / hp0 / hp0 / hp0 / hp0 / hp0 / hp0 / hp0. The effect of S042- as an intercalation anion is better. Because of the strong oxidation of sulfuric acid, the oxidation degree of the prepared GIC_s is higher. 2. Electrochemical intercalation exfoliation in Na_2SO_4 solution. The obtained GIC_s layer spacing increases with the increase of voltage and electrolyte concentration, and its stripping rate also increases. When the electrolyte concentration of Na_2S0_4 is 0.5 m, the voltage is 14 V. Electrochemical peeling was the fastest, the GIC_s layer spacing of the product changed from 0.3358 nm of graphite to 0.3381 nm, and the oxygen content was lower than 9.04% nm. Under the optimum conditions, the concentration of graphene dispersed in NMP was up to 11.47 mg / mL, and the yield was 37%. The concentration of graphene in PVP / water was 4.45 mg / mL, and the yield was 14.8%. The size of graphene was about 1 渭 m and the number of layers was less than 10 layers. The crystal structure is relatively complete and the ratio of C / O is high. The defects are mainly marginal defects. The sedimentation experiment shows that the dispersion is very stable .4.The graphene dispersion is used as the raw material of the electrode active substance. The graphene electrode supercapacitor was fabricated with a button-type structure. The assembly process of the capacitor was studied and the electrode forming pressure was discussed. The effect of binder content on the electrical properties of capacitors. The electrode was made with 10 MP_a molding pressure and 5 wt.% binder content. The specific capacity and energy density of graphene supercapacitor can reach 162F / g and 22.5 Wh/kg respectively under the constant current of 0.5 Ag in 6 mol/LKOH aqueous electrolyte. And has better charge and discharge cycle performance.
【學位授予單位】：華東理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TQ127.11

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